The invention discloses a preparation method of an alpha-phase ferric oxide/platinum hybridized nanoring, relating to a composite material. The invention provides a preparation method of an alpha-phase ferric oxide/platinum hybridized nanoring, which is capable of improving the photocatalytic activity of alpha-phase ferric oxide, simple in process and mild in condition. The preparation method comprises the following steps of (1) preparing a water-soluble ferric salt solution, and adding acid phosphate and sulfate; (2) carrying out ultrasound treatment on the solution obtained in the step (1), then, transferring the solution into a reaction kettle, sealing the reaction kettle, and heating to react; (3) cooling the solution to the room temperature after the reaction is complete, centrifugally separating precipitates at the bottom of the kettle, washing, and drying to obtain an alpha-phase ferric oxide nanoring; (4) preparing a chloroplatinic acid solution, then, sequentially adding absolute ethyl alcohol and the alpha-phase ferric oxide nanoring, carrying out ultrasound treatment, then, drying and collecting the obtained powder; and (5) immersing the powder obtained in the step (4) into ethylene glycol, heating to react, then, washing the product, and drying the product to obtain the alpha-phase ferric oxide/platinum hybridized nanoring.